CAIRO, Jan 4 (Reuters) - A bomb exploded under an armoured vehicle near the Egyptian North Sinai town of Areesh on Saturday, killing one army soldier and wounding at least two others, security sources told Reuters.

Armed men planted the explosive device on the road used by army vehicles in Egypt's campaign against militant Islamists in Sinai, the sources said. It went off when the armoured vehicle drove over it.

Egypt has struggled with security in the Sinai peninsula since the ouster of autocratic ruler Hosni Mubarak in 2011. Hardline Islamists exploited the security vacuum after Mubarak's fall to launch attacks into Israel and on Egyptian targets.

Violence surged in North Sinai, near the border with Israel, after the army overthrew the country's first elected Islamist leader Mohamed Mursi on July 3 last year, prompted by mass protests against his rule.

Egypt has since launched a wide crackdown against Mursi's Muslim Brotherhood, which it declared a terrorist group on Dec. 25. It has also stepped up its campaign to eradicate what it calls terrorist elements in Sinai. (Reporting by Youssry Ahmad, writing by Asma Alsharif)